Film chopping and sorting apparatus



Aug. 19, 1958 J. H. JUENGST ETAL 2, ,107

FILM CHOPPING AND SORTING APPARATUS Filed April 8. 1954 4 Sheets-Sheet 1A PLIFIER AMPL. l FIER RECORDER PUL. 5E

vJoImIiJueng-S'i mlwmlJEmemon INVENTORS' ATTORNEYS Aug. 19, 1958 J. H.JUENGST ETAL. 2,848,107

FILM CHOPPING AND SORTING APPARATUS Filed April 8. 1954 4 Sheets-Sheet 2Fig 2 W X WWW ATTORNEYS 9, 1958 J. H. JUENGST ET Al. 2,848,107

FILM CHOPPING AND SORTING APPARATUS Filed April 8, 1954 4 Sheets-Sheet 3INPUT CIRCUIT i c .90 F1 9r. J

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ATTORNEm Aug. 19, 1958 Filed April 8. 1954 J; H. JUENGST ETAL FILMCHOPPING AND SORTINGAPPARATUS 4 sheets-snet' 4 dig hi JbllnHJaengs-lHmuardJEmel-son INVENTORS arromvrw United States Patent fine 2,848,107Patented Aug. 19, 1958 FlLM CHOPPING AND SORTING APPARATUS John H.Juengst and Howard J. Emerson, Rochester,

N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., acorporation of New Jersey Application April 8, 1954, Serial No. 421,875

2 Claims. (Cl. 209-74) This invention relates to apparatus. for choppinga continuous strip or band of material. and for sorting the defectivesheets from the good sheets. It relates particularly to apparatus whichinspects the strip before chopping it to discover any defects and then.remembers or stores the information obtained at the scanning station soas properly to sort the sheets after the strip has been chopped into thesheets.

The main object of the invention is to provide a fast operating,durable, precise memory arrangement for such a chopping and sortingmachine.

Although a memory device may be required to store information forrelatively long intervals of, time such as a few seconds, minutes oreven longer, this is not the pertinent criterion when a large number ofitems, such as sheets are to be handled. When one wishes to handle a.hundred sheets per second for example, it is necessary to have a memorywhich takes in and dispenses information rapidly and precisely, whetherthe total storage time is long or brief. Thus a primary object of theinvention is to provide a memory device which is extremely fast in itsoperation with respect to receiving and dispensing the information whichit is to remember.

It is an object of certain preferred embodiments of the invention toprovide a memory device responsive not only to defects but also to otherinformation arbitrarily set into the memory device. The memory deviceaccording to the present invention is particularly suitable for handlingmany types of information and thus it makes possible exceptionallyconvenient operation of a complex sorting mechanism. I

The present invention is particularly useful with the optical inspectiondevice and with the electronic circuits described in two co-filedapplications by one of us, Howard J. Emerson, Serial Nos. 421,876 and421,877 (now U. S. Patent 2,719,235). useful with the mechanical sorterdescribed in patent application Serial No. 403,406, filed January 11,1954, by Gordon S. Rugg, now U. S. Patent 2,794,637.

According to the present invention a moving strip of film is inspected,optically or otherwise, in a manner which sets up in an electric circuita pulse corresponding to a defect in the strip at the inspectionstation. The strip is then chopped into discrete sheets and passed to asorter which rejects the defective sheets at a sorter station. Since thesorter station is at some distance from the inspection station, theremust be some means for remembering the defect pulse while the strip orsheets pass from the inspection station to the sorter station. For thispurpose, a layer of magnetic recording material is moved in a closedpath synchronously with the movement of the strip. The simplest form ofclosed path is the surface of a rotating drum carrying the magneticrecording material. Alternatively the magnetic material may be on a beltmoving in some closed path over suitable rollers.

Magnetic recording materials are well known and are available coated onthe surface of cylindrical drums or It is also particularly ning stationon the strip.

coated on elastic bands which may be stretched around a cylindrical drumor over suitable rollers. Such magnetic material is normally used forrecording informattion such as sound or video signals to form a soundtrack or information track. The present invention does not record atrack but merely records a pulse. There is no common name for such arecord. It cannot be called the pulse itself since it does notnecessarily move. It may be thought of as a magnetic pip but is herereferred to simply as a magnetic spot on the material.

At a given point along the closed path or along the circumference of thedrum there is a magnetic recording head for impressing a magnetic spoton the magnetic material for each defect pulse. Thus the point at whichthe recording head is located corresponds to the scan- As the magneticmaterial moves along the path, it arrives at a point corresponding tothe sorter station and at this point there is located a magneticplayback head. The playback head is connected to the sorter to reject asheet when a magnetic spot passes the playback head. The statement thatthe locations of the recording and playback heads correspond to thescanning and sorting stations requires some explanation, particularly inthe embodiments of the invention which involve a second memory device inseries with the magnetic one either ahead of it or after it. Theseembodiments are described in more detail below. The purpose of thesecond memory device is to remember the defect pulse for a time intervalequal to the strip travel time from the defect in question to the end ofthe sheet having the defect, so that the sorting operation always takesplace at the same time with respect to each sheet no matter where alongthe sheet the defect occurs.

In the case where this second memory device is electrically ahead of themagnetic device, the recording head is located at a point correspondingto the inspection station but the magnetic spot is not recorded until(what is to become) the end of the sheet passes the inspection orscanning station. The playback head is at the point corresponding to thesorter station. Incidentally, this correlation of locations covers minoradjustments or settings which allow for the time for a sorter solenoidto operate, as will be described later.

In the case where the second memory device is electrically after themagnetic device, the recording head is again at the point correspondingto the inspection station and records a spot as a defect passes theinspection station. The playback head reacts to the magnetic spots andis at the point corresponding to the sorter station,

but the sorter does not operate until the end of the sheet is past.

In both cases, the playback head and recording head are separated alongthe path a distance corresponding to the strip travel time from theinspection station to the sorter station (allowance being made for anysorter operating time by selection of the point defined as the sorterstation).

It is necessary to have an erasing head between the playback head andthe recording head to remove the magnetic spot after it has passed theplayback head.

When strips which are to be inspected and chopped are spliced orotherwise joined together, the splice will act as a defect and one sheetcontaining the defect will be rejected by the sorter. However, it isoften desirable to reject two or three sheets before the splice and twoor three sheets after the splice in order to be absolutely sure that nosheets are accepted by the sorter which carry fingerprints or the likeincurred by the making of the splice. The present invention isparticularly adapted to reject a plurality of sheets near a splice in avery simple manner. Additional recording heads are located along thememory path (for example, on either side of the primary recording head)separated by distances corresponding to the length of one sheet. After asplice has been made, the operator merely watches until the splice isunder the inspection station. He then presses a suitable button toenergize all of the auxiliary recording heads (and perhaps also toenergize the primary recording head) so that several spots arrive insuccession at the playback head and several sheets are automaticallyrejected by the sorter. It may be diflicult to operate on the fly as thesplice is moving rapidly under the inspection station. Therefore apreferred system has the auxiliary heads all located at fixed distanceahead of the main recording head on the memory path and may include onecorresponding to the splice itself. While the machine is stopped and thesplice is made at a corresponding fixed distance ahead of the inspectionstation, the button is pressed to record the auxiliary spots. The splicepasses the inspection station as its auxiliary spot passes the mainrecording head and a second spot is superimposed on the first or nearby.

This principle is applicable Wherever one wishes to reject a sheet atsome selected distance from the inspection station. To do this there is,in addition to the primary inspection head, one additional recordinghead spaced a corresponding distance along the path from the defect orprimary recording head.

As described in the Rugg application mentioned above, the sortermechanism may be quite complex and may, for example, sort the sheetsinto three groups, the third group being for routine test purposes. Forexample, when several sheets ahead of a splice are being rejectedanyway, it is customary to select one of these representing the end ofone supply roll, as a sample of the supply roll. The magnetic memorydevice according to the present invention lends itself particularly wellto the operation of such auxiliary mechanisms. A separate recording headis located to one side of the main magnetic path and a separate playbackhead picks up any magnetic spot caused by this auxiliary recording head.In the present example this separate recording head is actuated by amanual switch as a splice between two rolls is made. A pulse from thesecond playback head is used to operate the auxiliary mechanism of thesorting device to select sheets for the third group. The sortingmechanism described by Rugg also counts the sheets and separates theminto groups of 25. Additional recording heads are arranged transverselyacross the magnetic material with additional playback heads to pick upany magnetic spots recorded by these additional recording heads tooperate the counting and separating mechanism so that when the end ofone supply roll is reached, all of the sheets from that roll will beremoved from the machine, even if a full has not been reached and allthree bins for receiving the sheets from the sorter will be emptiedbefore sheets from the new roll start to come off the sorter.

A preferred embodiment of the invention includes a second stage ofmemory to permit operation of the sorter at precisely the same momentwith respect to each sheet passing the sorter. A defect may occuranywhere along a particular sheet, but precise operation requiressorting at the same point with respect to the sheet each time, say atthe end of the sheet. According to one form of this double memorysystem, the pulse from the inspection station is fed to the magneticmemory at the moment the band passes the inspection station. This pulseis recorded as a magnetic spot which creates a pulse in the playbackhead when it arrives at the playback head. This pulse is fed to a secondmemory device, and is stored in this second memory device until thewhole of a sheet has passed the sorting station. Additional defectscause additional pulses but do not alter the condition of the secondmemory device. For example, the second memory device may include a glowlamp which Ill 4 is turned on whenever a pulse is received from theplayback head.

Pulses are taken cyclically from the second memory device every time asheet has completely passed the sorting station. If there are no defectsrecorded in the second memory device, for example, if the glow lamp hasnot been turned on, no pulse is fed to the sorter and the sheets pass tothe accept group. If, however, a defect pulse has been recorded in thesecond memory device, i. e., the glow lamp is on when the cycle iscomplete, a pulse is passed to the sorter to reject the sheet. At thesame time the glow lamp is turned off and will remain 01f until anotherdefect pulse (i. e., from some later sheet) is received from themagnetic playback head.

The effect of this second memory is to store up all of the defects untilthe end of the sheet is reached and then to operate the sortingmechanism to reject the sheet if any defects have been recorded. Thusthe sorting mechanism operates at exactly the same point with respect toeach sheet. This insures more positive operation of the sorter and henceis preferred.

The two memory systems are in series and it does not matter which comesfirst. Thus another form of the double memory system has the pulse fromthe inspection station fed to the cyclical storage from which it isreleased at the time corresponding to the end of a sheet (even thoughthe strip has not been chopped into sheets at this point). The output ofthe cyclical memory is then fed to the magnetic recording head.

The cyclical memory may take any form but it is preferable to have afast operating one so that the band may be run at high speed and thustake full advantage of the high speed afforded by the magnetic memorysystem.

r Various forms of cyclical memories are described below.

When the cyclicalmemory is ahead of the magnetic memory, the magneticspots are always recorded at points corresponding to the end of sheets.If the circumference of the drum exactly equals an integral number ofsheets, these points are the same every time the drum rotates. That is,there may be exactly 8 or 10 or 15 such points and the magnetic materialaround the circumference between these points is not used. In fact, inorder to minimize the possibility of a false signal due to noise in themagnetic material, these inbetween areas of magnetic material may beremoved. This refinement has not been found necessary in practice,however.

In connection with this whole idea of a two memory system, it is pointedout that simple mechanical memories usually do not need a cyclicalmemory. For example, mechanical memories relying on the setting ofmovable pins arranged on the circumference of a rotating wheel mayemploy a relatively wide member to engage the pin, but the pinsthemselves are spaced to correspond to the end of the sheets. However,mechanical memories are slow. Thus cyclical memories find their greatestimportance in combination with magnetic memories since magnetic memoriesare fast and are able to utilize their speed to 'maximum efficiency whencombined with cyclical memories.

Also, the present two memory system should not be confused with dualsystems which operate with respect to different parts of a conveyor suchas systems which slit a strip and then chop the two parts into differentsize sheets or move the two sets of sheets at different speed. In thepresent invention, the sheets in general move at about the same speed asthe strip but this is not a pertinent factor and the sheet conveyorcould move at a different speed from the strip. The present doublememory system is concerned merely with the total travel time between theinspection station and the sorter station which is all handled by themagnetic memory (no matter what the relative speeds of the strip andsheets are) and the exceedingly brief delay to make all random defectseffecti ve at the end of the sheet which is handled by the cyclicalmemory.

The invention, will be more fully understood from the followingdescription when read in connection with the accompanying drawings inwhich:

Fig. 1 is a schematic perspective view of an inspecting, chopping andsorting device according to the present invention;

Fig. 2 is a vertical section of one form of magnetic memory according tothe present invention;

Figs. 3 and 4 show alternative cyclical memory circuits either of whichmay be combined with Fig. l in either of two ways;

Fig. 5 shows a simple cyclical relay circuit which also may be combinedwith Fig. 1 in either of two ways; and

Figs. 6 and 7 illustrate complete double memory circuits.

In Fig. 1 a strip 10 of film or other material is driven over a roller11 and past an inspection station 12. Light from a lamp 15 throughlenses 16 and 17 illuminates a transverse line of light at theinspection station 12 and the light transmitted by the band 10 isdirected by a lens 13 to a photoelectric cell 19. This arrangementinvolves optical inspection by transmitted light. Alternatively theinspection may be by reflected light as shown in the two Emersonapplications mentioned above. Greater sensitivity is obtainable byflying spot scanning (either reflected or transmitted) but the presentinvention is not limited to any particular type of inspection system.

After it passes the inspection station 12, the film band passes througha chopper schematically shown as a knife and a table made up of parts 26and 27. The band is chopped into sheets 28 which are simultaneouslygrasped by clamps 31 mounted on the outside of a drum 32. By means of adrive roll 33 and drive belt 34 connected to the roller 11, the drum 32is driven synchronously with the film strip 10. The drum and clampingarrangement is described in more detail in the Rugg applicationmentioned above. For the present invention, it is sufiicient to pointout that the clamps 31 are normally closed but may be held open by studsor other devices engaging the cam surface 42 which constitutes the endof each clamp 31 extending beyond the rim of the drum 32. The stud foropening each clamp and for allowing it to close on each sheet as itcomes from the chopper is shown at 30.

As the drum 32 rotates carrying the discrete sheets with it, the camsurfaces 42 arrive under a plunger of a solenoid 41. In the preferredsystem the plunger 40 is normally extended so as to open the clamps,thereby dropping the good sheets of film into the first bin 43. In thiscase rejection consists of holding on to the sheet and carrying it pastthe sorter station at 40. This will be referred to as the first sortersystem and alternative systems will be described below.

in any of the systems, if the plunger 40 is drawn into the solenoid 41,the clamp remains closed and the film sheet is carried forward until thecam surface strikes the plunger 45 or the fixed stud 46. The plunger 45is normally held up by the solenoid 48 so that all sheets which pass thebin 43 are normally carried to the bin 47. The stud 46 is fixed inposition and no films are carried past the bin 47. If the plunger 45 islowered, films will be dropped into the bin 49.

A defect in the film passing the scanning station 12 causes a change inthe intensity of the light falling on the cell 19 and hence causes asignal pulse to pass to the pulse amplifier circuit 55. According to theinvention this pulse causes a magnetic recording head 56 to record amagnetic spot on the magnetic material carried on the surface of a drum53, which through a worm gear 52 and a worm 51 is driven synchronouslywith the roller 11 and hence synchronously with the film 10. The pointat which the recording head 56 is located with respect to thecircumference of the drum 53 corresponds to the scanning station 12 onthe film. As the defect moves from the scanning station 12 under thechopper 25'and onto the gripper ,drum 32, the magnetic spot on the drum53 rotates steadily. As the sheet of film with the defect arrives at theplunger 40, the magnetic spot arrives at the corresponding point aroundthe drum 53. At this corresponding point, there is located a magneticplayback head 57 which through an amplifier circuit 58 causes a signalwhich in turn energizes the solenoid 41 and draws the plunger 40 up sothat the sheet is not released into the accept bin 43 but is rejectedand continues on the drum 32. Since the plunger 45 is normally held up,this reject sheet normally passes to the stud 46 which dumps the rejectsheets into the bin 47.

in addition to the primary defect recording head 56, four otherrecording heads 61 are located along the same path as far as themagnetic material is concerned. The distances between the successiverecording heads are each equivalent to one sheet of the chopped film. Inthe example shown, when an operator splices on a new supply roll, hewaits until the splice is at the inspection station 12. Then, by meansof a recorder 62, he energizes all four of the recording heads 61 whilethe splice itself is energizing the recording head 56. This causes fivesuccessive magnetic spots on the drum53. These spots, as they arrive atthe playback head 57' cause five successive sheets to be rejected anddumped into the bin 47. This insures that two sheets ahead of eachsplice and two sheets following each splice are rejected as well as thesplice sheet itself; The recorder 62 may also be connected to therecording head 56 in order to be doubly sure that the splice records asa defect.

At. the same time as the operator is imposing the five magnetic spots onthe main pathof the magnetic memory, another spot is recorded by arecord head 65 located to one side of the main path. This is referred toas being recorded at a different level on the memory drum. As thismagnetic spot arrives at a playback head 66, the amplifier circuit 67associated therewith causes the solenoid 48 to release the plunger 4sothat a sheet which passes the point 441 is released at the point 45 anddropped into the middle bin 49. In the example shown, the second lastsheet before the splice is rejected so that it does not fall in the bin43 but is then purposely picked out into the bin 49 to be used forroutine testing of the sheets.

A second sorter system will now be described. It differs only slightlyfrom that shown in Fig. 1. In the second system, the head 57 is spacedslightly farther from the head 56 and the output of circuit 58'de-energizes solenoid 48 (to reject defects into bin 49) instead ofenergizing solenoid 4'1. Acceptable sheets pass to bin 47'. The outputof circuit 67 is connected to solenoid 41 to deposit test sheets in bin43 with the spacing between heads 65 and 66 set to select the sheetdesired. The advantage of this second system is in the simplified designof the defect sorting plunger (in this case 45) since the plunger nevertouches the cam surfaces 42 of the clamps 31 except when a defect ispresent. However, in either system it is preferable to have a secondmemory stage as described in connection with Figs. 3 to 7 so that thereject operation occurs at the end of a sheet no matter where on thesheet the defect occurs.

In Fig. l the auxiliary recording heads 61 are shown located on bothsides of the main defect recorder head 56. It is preferable to make thesplice some distance in advance of the inspection station 12. Forexample, the machine may be stopped when the end of a supply roll isreached and the next supply roll spliced on with the splice near theroller 11. Also, it is preferable to operate the recorder 62 while themachine is stopped. Therefore, it is preferable to have the auxiliaryrecording heads 6i at a distance ahead of the defect head 56corresponding to the distance the splice and neighboring areas are aheadof the inspection station when the machine is stopped. Otherwise, afterthe splice is made the machine must be started and the manual recorder62 oper- T! ated on the fly as the splice pases the inspection station.

The number of auxiliary heads 61 or 65 is not critical. If one desiresto reject seven sheets at each splice, seven recording heads are used onthe top level of the drum. If one wishes to perform various otherfunctions in addition to sorting out the rejects, additional levels ofthe recording drum may be used. The selecting of the second last sheetfor a test sheet is only one of these additional functions. The Ruggapplication referred to above, counts the sheets into groups of 25. Inpractice it is customary to use a third level of the drum to index thecounting paddles twice at the end of each roll and to use a fourth levelto stop the whole machine when the splice sequence is complete so thatall sheets from the old roll may be removed from the bins 43, 47 and 49before sheets from the new roll start to come off the sorter.

After the magnetic spots have been read by the playback heads 57 and 66,they are erased in the usual way by magnetic erasers 68.

As shown in Fig. 2, the magnetic drum may be made up of a cylinder 71having four standard elastic magnetic bands 72, 73, 74, 75 stretchedtightly thereon. In this case, each of the four levels of the magneticmemory is located on a difierent band. Alternatively the magneticmaterial may be uniformly coated directly on the drum itself. In thiscase the different magnetic paths or levels are different areas on thesame magnetic surface. Each recording or playback head 57 may be of thestandard form having a magnetic core 76 with or without a very small gapbetween it and the magnetic recording material. Any of the standardtypes of magnetic recording heads for surface recording may be used withthe present invention.

In a preferred embodiment of the invention the defect pulse isremembered in two stages. This embodiment may be identical with thatshown in Fig. 1 except for the detail illustrated in Figs. 3, 4 and ormay have the arrangement shown schematically in Fig. 6 or Fig. 7.

In Fig. 3 the worm 51 and worm gear 52 of Fig. 1 are shown. An electriccommutator 80 having metal inserts 81 in the rim thereof rotates withthe worm shaft 51. Each time contact is made by one of the inserts 81joining brushes 82, an electric circuit 83 sends a pulse across acondenser 84. This pulse is referred to as a synchronizing or sync pulseand the device is arranged so that one such pulse is produced for eachsheet of film. This sync pulse is fed to the control grid of a thyratron85 which is normally on. synchronizing pulse has no effect and the tube85 stays A defect pulse from the unit labeled 90 is fed through acondenser 91 to the control grid of a similar thyratron 95 which isnormally off. If the tube 95 is off, this defect pulse turns it on whichcauses the cathode of the tube 95 to go slightly positive andincidentally to turn on the indicator glow tube 96. At the same time,the turning on of the tube 95 causes a definite positive pulse to flowthrough the capacitor 92 which momentarily raises the potential of thecathode and the second grid of the thyratron 85 relative to its plate sothat the thyratron 85 goes out. A small indicator tube 86 also goes outand the potential of the cathode of the thyratron 85 as measured at thepoint 87 drops to zero. The effect of the positive pulse across thecapacitor 92 and the subsequent dropping of the potential of the point87 to zero on the output amplifier circuit 97 will be described below.Sufiice it to say here that neither the positive pulse nor the negativeswing in potential has any effect which passes through the circuit 97.Therefore, there is no effective output when .a defect pulse from thecircuit 90 arrives. However, such a defect pulse does turn the thyratron95 on and the thyratron 85 off.

When the end of a sheet arrives, a sync pulse from If the thyratron 85is on, the

the condenser 84 turns the thyratron on again and by a positive pulsethrough the condenser 92 turns the thyratron 95 off thus resetting it toreceive another defect pulse.

It will be noted that a positive pulse goes to the output 97 whenevereither the tube 95 is turned on and the tube 85 is turned off or thetube 85 is turned on and the tube 95 is turned off. However, there is avery important difference. When the tube 85 is on, which is its normalstate, the potential at the point 87 is relatively high and the positivepulse is superimposed on this already high potential. Thus when the tube95 is turned on, the pulse is superimposed on a high potential as itgoes to the output 97 (and as it turns otf the tube 85). However, whenthe tube 85 is turned on, the point 87 has been at zero potential andthe positive pulse is superimposed on this zero potential as it goes tothe output 97 which is set to react to such a pulse and to pass thepulse to the circuit or load 98 which may be either a magnetic recordinghead or a reject solenoid.

Circuits operating as the above described circuit 97 are well-known. Oneof the most common forms consists of two tubes in series with arelatively high positive bias so to be practically at their saturationpoint. For example, a 6AU6 voltage amplifier tube in series with a 6AQ5power amplifier tube both biased to zero work well in practice. Zerobias is relatively high positive since these tubes are normally biasednegatively. Taking the three situations in turn, it is noted that whenthe tube is on, the point 87 is highly positive and the first tube incircuit 97 is biased to about zero. A positive pulse caused by turningon the tube 95 raises the potential of the point 87 and makes the biason the first tube in the output circuit 97 still higher but since it isat the saturation point, no signal passes through the first tube in thecircuit 97. When this pulse turns the tube 85 off, the potential on thepoint 87 swings quite negative which passes a high negative signal tothe first tube of the circuit 97 which passes this negative signal as apositive signal due to the usual inversion in the tube and the secondtube of the circuit 97 is biased already at its saturation point so thatthe positive signal received from the first tube is not passed. Thusneither the positive pulse nor the negative swing is effective in theoutput of the circuit 97.

4 However, the third case comes up when the tube 85 is turned on and thetube 95 is turned off.

In this case the point 87 starts at ground potential and goes positiveso that a positive pulse arrives at the first tube in circuit 97 whichis below saturation because it is biased negatively. The first tube incircuit 97 passes this positive pulse and inverts it sending a largenegative pulse to the second tube, which, of course, passes the negativepulse as a positive pulse to operate the unit 98.

Thus defect pulses, no matter where they occur in a sheet, aretemporarily stored and released at the end of the sheet. If no defectpulse occurs, the thyratron 85 and the indicator glow tube 86 stay onconstantly.

This synchronous or cyclical memory may be electrically in series withthe magnetic memory in either order. That is, the pulse input circuit 90may correspond to the photoelectric cell circuit 55 of Fig. l in whichcase the unit or load 98 represents the recording head 56 of Fig. 1.Alternatively, the pulse input circuit 90 may be the playback head 57 ofFig. l in which case the unit 98 represents the solenoid 41 of Fig. 1.

The above arrangement will operate at extremely high speed and hasproven quite practical for handling a large number of sheets per second.Another arrangement which will operate at reasonably high speed isillustrated at Fig. 4. In this arrangement the synchronizing pulses areprovided by an apertured disk 100 turning on the worm shaft 51 andhaving a series of apertures 101 through which light shines on aphotocell 102 to provide a pulse in the amplifier 103. However, suchpulses do not occur every time since the light source for illuminatingthe apertures 101 is a glow tube 1% which is turned off and on by athyratrcn referred to as a defect" thyratron located in unit 106. Thisthyralron is normally off but may be turned on by a defect pulse from aunit which is labeled 90 to correspond to Fig. 3. When a defect pulsearrives from the unit 90, the thyratron 1% turns on the glow lamp 1% andit remains until one of the apertures ltil passes in front of this glowlamp M5. The pulse received on the phototube 16-2 and passed throughamplifier 1% then does two things. Primarily this pulse passes to anoutput amplifier 16*? to operate an output device or load labeled i l;to correspond to 3. At the same time it turns on a reset thyratron lttclwhich turns of? the defect thyratron we, thus resetting it to receiveany subsequent defect pulses. As before, the unit M may be either theinspection photocell in which case unit 98% is the magnetic recordinghead or the unit 9t may be the playback head in which case the unit 93is the reject solenoid of the system.

Fig. 5 shows a somewhat slower operating cyclical memory employingelectromagnetic relays. As before, a commutator 8i mounted on the wormshaft has metal inserts to provide synchronous pulses through brusheslit), ill and 7112. Normally the relays H5, lllti, ll? and lit; are asshown and no power flows from and through the circuits E28, 121 and 125which include (or are con nected to) a source of electric power.However, when pulse arrives from the input circuit 92*, this pulsecloses the electromagnetic relay 115 which causes current f-om the powercircuit 123 to flow through contacts i2; to keep the relay 115 closed sothat this current continues to flow and energizes the relay lllllclosing it out no current flows from the power circuit 125 since therelay lid is still open. This state continues until one of the metalinserts fil connects brushes Md and ill causing cu rent from the powercircuit 12d to flow in the relay 11.3 closing it so that the circuit 125then delivers a pulse to the output unit or load 93. The disk 8i?continues to rotate so that the insert 81 then joins up brushes Hit andH2 (as well as 111) which, by current from the power circuit 124),causes the relay 116 to open. This stops all current from the powercircuit 121 and de-energizes relays 115 and 117 thus resetting them(open) to receive any subsequent detect pulse from the input circuit tl.The relays require a fraction of a second to operate and hence thissystem is not as rapid as the purely electric systems shown in Figs. 3and 4. As before, the input unit 90 may be either the inspectionphotocell or the play-- back head and the load d8 may be the recordinghead or the reject solenoid.

The alternative combinations are shown in Figs. 6 and 7. In bothfigures, a film band 131) passes between drive rollers 131 past aninspection station 12 and through subsequent rollers 132 to a choppersymbolically shown as a knife 133. The sheets from the chopper i553 passeither to bin 135 or 136 depending on whether the sloping table or chute137 is in the position shown or is raised by the solenoid M9 to thelocation represented by broken lines 141. A synchronizing pulse incircuit 1 1-5 as provided by commutator 146 is fed to a cyclical memorysystem indicated as 147 in Fig. 6 and as 148 in Fig. 7.

In Fig. 6 a defect pulse from photocell ti is fed to the cyclical memoryl l'l' and is stored until the end of .1, l and 5 and is thentransmitted to a recording h lot) which records a magnetic spot on arotating ma drum driven synchronously with the drive rollers asindicated by the broken linelfiil. A playback heat 155 responds to sucha magnetic spot and through an amplifying circuit 156 operates thesolenoid 14b to i. the table 13? to the position shown by broken lineslei thus causing the defect sheet to go in the bin ass.

In Fig. 7 a defect pulse from the phototube 19 is fed to a circuit 55and through a recording head 56 is reof the stripping or dropping point.

10 corded on the synchronously driven magnetic drum 53 to be picked by aplayback head 57, all corresponding to Fig. 1. This defect pulse fromthe playback head 57 does not operate the solenoid 14 d immediately,however, but rather is fed to a cyclical memory 148 and held there untila synchronous pulse through circuit 145 arrives, at which time the pulseis fed to the solenoid 1140 to raise the sorting table 137 so that thedefective sheet is sent to bin 136.

In either case, if no defect pulses are produced, no pulses are sent tothe solenoid and hence the table 137 stays in the lower position so thatgood sheets fall into bin 135.

The time required for the mechanical operation of any type of sortermust be allowed for and, at the high speed at which the preferredembodiments of the present invention operate, the sorting station may bedefined as being for example about A of a sheet length ahead Theselection of this location is purely for mechanical reasons depending onthe type of sorting device used. Referring back to Fig. 1, this factor,namely, the time required to operate a solenoid and drop a sheet of filmmay have, for example, the following effect spelled out in terms of thesheet length, the operation of the retimer or resetting mechanism andthe time of operation of the dropping cam. The location of a defectalong a sheet varies of course. While the sheet itself moves from aposition 1% sheet lengths ahead of the dropping point to within inch of/4 of a sheet length ahead of this point, any defect pulse is stored bythe cyclical memory (which follows the magnetic memory in this example).When the point of a sheet length ahead of the actual dropping point isreached, the defect pulse is fed to the solenoid and the retimer (orcyclical memory) is reset by the synchronous pulse. This raises thedropping cam and the gripper carries the defective sheet past thedropping plunger (40 in Fig. 1) without interruption. The dropping camor plunger then stays actuated until the next sheet reaches the point ofa sheet length ahead of the drop point. If the retirner has not beenupset by another defect pulse, a synchronous pulse from the cyclicalmemory resets the dropping cam. If the retimer has been upset by adefect pulse, the resetting of the retimer prevents the resetting of thedropping cam so that this sheet too is rejected, i. e., remains gripped.The term sorting station refers to the point at which the films aredropped or to some point a slight distance ahead of this point such as a4 sheet length in the example just given, to allow for the mechanicaltime of operation of the cams, grippers or other sorting mechanism. Thislatter example has been discussed merely to insure that the term sorterstation is interpreted to take into account spacings allowed for thetime of mechanical operation.

We claim: I

1. In a strip chopping and sorting device having means for moving thestrip past an inspection station, a chopper for receiving the inspectedstrip and for chopping it into sheets of uniform length, and a sorterfor receiving the sheets in succession at a sorter station and forrejecting the defective ones, the combination of means for setting up inan electric circuit a pulse corresponding to a defect in the strip atthe inspection station, a layer of magnetic recording material moving ina closed path synchronously with said strip moving means, a magneticrecording head at a point on the path and connected to the pulse settingup means for impressing a magnetic spot on the material for each defectpulse, a magnetic playback head similarly positioned relative to thepath at a distance from the recording head corresponding to the time ofstrip travel from the inspection station to the sorter station, meansconnected to and controlled by the playback head for operating thesorter to reject the corresponding sheet when a magnetic spot passes theplayback head and a magnetic erasing head on said path between theplayback and recordingheads, which'device in addition to sorting intoaccept and reject groups also sorts out a third group, said combinationhaving a second recording head to one side of the line of magneticmaterial which passes under the defect pulse recording head, forrecording a separate spot on the magnetic material means for operatingthe second recording head independently of the defect pulse setting upmeans, a second sorter aligned with the first sorter for receiving thesheets, a second playback head aligned with the second recording headand means connected to and controlled by the second playback head foroperating the second sorter to sort into said third group when amagnetic spot passes under the second playback head.

2. In a strip chopping and sorting device having means for moving thestrip past an inspection station, a chopper for receiving the inspectedstrip and for chopping it into sheets of uniform length, and a sorterfor receiving the sheets in succession at a sorter station and forrejecting the defective ones, the combination of means for setting up inan electric circuit a pulse corresponding to a defect in the strip atthe inspection station, and means for operating said sorter inaccordance with said defect pulse including two memory circuits inseries, one receiving said defect pulse from the setting up means andproducing a second pulse after an interval of time and the otherreceiving said second pulse and after another interval of time producinga third pulse which operates said sorter, the interval of time for oneof said memory circuits corresponding to the time required for the strip12 to travel from the inspection station to the sorter station and theinterval of time for the other memory circuit being variable andcorresponding to the time required for the strip to travel the distancebetween the defect and the end of the sheet having the defect, in whichthe memory circuit whose interval of time corresponds to strip travelfrom the inspection station to the sorter station, consists of a layerof magnetic recording material moving in a closed path synchronouslywith the strip moving means, a magnetic recording head positioned at apoint on the path for receiving a pulse and for impressing a magneticspot on the material for each defect pulse and a magnetic playback headsimilarly positioned relative to the path at a distance along the pathfrom the recording corresponding to the time of strip travel from theinspection station to the sorter station, for producing a pulse when amagnetic spot passes the playback head.

References Cited in the file of this patent UNITED STATES PATENTS2,306,211 Geiss Dec. 22, 1942 2,433,685 Dowell Dec. 30, 1947 2,534,070Schmidt et al. Dec. 12, 1950 2,535,353 Drake et al. Dec. 26, 19502,614,169 Cohen et al. Oct. 14, 1952 2,693,277 Wagner et a1. Nov. 2,1954 FOREIGN PATENTS 692,655 Great Britain June 10, 1953

